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man(1) man(1)
NAME
man - format and display the on-line manual pages
SYNOPSIS
man [-acdfFhkKtwW] [--path] [-m system] [-p string] [-C config_file]
[-M pathlist] [-P pager] [-B browser] [-H htmlpager] [-S section_list]
[section] name ...
DESCRIPTION
man formats and displays the on-line manual pages. If you specify sec-
tion, man only looks in that section of the manual. name is normally
the name of the manual page, which is typically the name of a command,
function, or file. However, if name contains a slash (/) then man
interprets it as a file specification, so that you can do man ./foo.5
or even man /cd/foo/bar.1.gz.
See below for a description of where man looks for the manual page
files.
OPTIONS
-C config_file
/etc/man.config. (See man.config(5).)
-M path
Specify the list of directories to search for man pages. Sepa-
rate the directories with colons. An empty list is the same as
not specifying -M at all. See SEARCH PATH FOR MANUAL PAGES.
-P pager
Specify which pager to use. This option overrides the MANPAGER
environment variable, which in turn overrides the PAGER vari-
able. By default, man uses /usr/bin/less -is.
-B Specify which browser to use on HTML files. This option over-
rides the BROWSER environment variable. By default, man uses
/usr/bin/less-is,
-H Specify a command that renders HTML files as text. This option
overrides the HTMLPAGER environment variable. By default, man
uses /bin/cat,
-S section_list
List is a colon separated list of manual sections to search.
This option overrides the MANSECT environment variable.
-a By default, man will exit after displaying the first manual page
it finds. Using this option forces man to display all the man-
ual pages that match name, not just the first.
-c Reformat the source man page, even when an up-to-date cat page
exists. This can be meaningful if the cat page was formatted
for a screen with a different number of columns, or if the pre-
formatted page is corrupted.
-d Don’t actually display the man pages, but do print gobs of
debugging information.
-D Both display and print debugging info.
-f Equivalent to whatis.
-F or --preformat
Format only - do not display.
-h Print a help message and exit.
-k Equivalent to apropos.
-K Search for the specified string in *all* man pages. Warning:
this is probably very slow! It helps to specify a section.
(Just to give a rough idea, on my machine this takes about a
minute per 500 man pages.)
-m system
Specify an alternate set of man pages to search based on the
system name given.
-p string
Specify the sequence of preprocessors to run before nroff or
troff. Not all installations will have a full set of preproces-
sors. Some of the preprocessors and the letters used to desig-
nate them are: eqn (e), grap (g), pic (p), tbl (t), vgrind (v),
refer (r). This option overrides the MANROFFSEQ environment
variable.
-t Use /usr/bin/groff -Tps -mandoc to format the manual page, pass-
ing the output to stdout. The default output format of
/usr/bin/groff -Tps -mandoc is Postscript, refer to the manual
page of /usr/bin/groff -Tps -mandoc for ways to pick an alter-
nate format.
Depending on the selected format and the availability of printing
devices, the output may need to be passed through some filter or
another before being printed.
-w or --path
Don’t actually display the man pages, but do print the loca-
tion(s) of the files that would be formatted or displayed. If no
argument is given: display (on stdout) the list of directories
that is searched by man for man pages. If manpath is a link to
man, then "manpath" is equivalent to "man --path".
-W Like -w, but print file names one per line, without additional
information. This is useful in shell commands like man -aW man
| xargs ls -l
CAT PAGES
Man will try to save the formatted man pages, in order to save format-
ting time the next time these pages are needed. Traditionally, format-
ted versions of pages in DIR/manX are saved in DIR/catX, but other map-
pings from man dir to cat dir can be specified in /etc/man.config. No
cat pages are saved when the required cat directory does not exist. No
cat pages are saved when they are formatted for a line length different
:
from 80. No cat pages are saved when man.config contains the line
NOCACHE.
It is possible to make man suid to a user man. Then, if a cat directory
has owner man and mode 0755 (only writable by man), and the cat files
have owner man and mode 0644 or 0444 (only writable by man, or not
writable at all), no ordinary user can change the cat pages or put
other files in the cat directory. If man is not made suid, then a cat
directory should have mode 0777 if all users should be able to leave
cat pages there.
The option -c forces reformatting a page, even if a recent cat page
exists.
HTML PAGES
Man will find HTML pages if they live in directories named as expected
to be ".html", thus a valid name for an HTML version of the ls(1) man
page would be /usr/share/man/htmlman1/ls.1.html.
SEARCH PATH FOR MANUAL PAGES
man uses a sophisticated method of finding manual page files, based on
the invocation options and environment variables, the /etc/man.config
configuration file, and some built in conventions and heuristics.
First of all, when the name argument to man contains a slash (/), man
assumes it is a file specification itself, and there is no searching
involved.
But in the normal case where name doesn’t contain a slash, man searches
a variety of directories for a file that could be a manual page for the
topic named.
If you specify the -M pathlist option, pathlist is a colon-separated
list of the directories that man searches.
If you don’t specify -M but set the MANPATH environment variable, the
value of that variable is the list of the directories that man
searches.
If you don’t specify an explicit path list with -M or MANPATH, man
develops its own path list based on the contents of the configuration
file /etc/man.config. The MANPATH statements in the configuration file
identify particular directories to include in the search path.
Furthermore, the MANPATH_MAP statements add to the search path depend-
ing on your command search path (i.e. your PATH environment variable).
For each directory that may be in the command search path, a MAN-
PATH_MAP statement specifies a directory that should be added to the
search path for manual page files. man looks at the PATH variable and
adds the corresponding directories to the manual page file search path.
Thus, with the proper use of MANPATH_MAP, when you issue the command
man xyz, you get a manual page for the program that would run if you
issued the command xyz.
In addition, for each directory in the command search path (we’ll call
it a "command directory") for which you do not have a MANPATH_MAP
statement, man automatically looks for a manual page directory "nearby"
namely as a subdirectory in the command directory itself or in the par-
ent directory of the command directory.
You can disable the automatic "nearby" searches by including a NOAU-
TOPATH statement in /etc/man.config.
In each directory in the search path as described above, man searches
for a file named topic.section, with an optional suffix on the section
number and possibly a compression suffix. If it doesn’t find such a
file, it then looks in any subdirectories named manN or catN where N is
the manual section number. If the file is in a catN subdirectory, man
assumes it is a formatted manual page file (cat page). Otherwise, man
assumes it is unformatted. In either case, if the filename has a known
compression suffix (like .gz), man assumes it is gzipped.
If you want to see where (or if) man would find the manual page for a
particular topic, use the --path (-w) option.
ENVIRONMENT
MANPATH
If MANPATH is set, man uses it as the path to search for manual
page files. It overrides the configuration file and the auto-
matic search path, but is overridden by the -M invocation
option. See SEARCH PATH FOR MANUAL PAGES.
MANPL If MANPL is set, its value is used as the display page length.
Otherwise, the entire man page will occupy one (long) page.
MANROFFSEQ
If MANROFFSEQ is set, its value is used to determine the set of
preprocessors run before running nroff or troff. By default,
pages are passed through the tbl preprocessor before nroff.
MANSECT
If MANSECT is set, its value is used to determine which manual
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发表于 2009-04-29 10:08
